Categories

Statistics

View count:

65,348

Likes:

298

Dislikes:

29

Comments:

49

Duration:

04:11

Uploaded:

2015-10-30

Last sync:

2019-06-13 15:30

So, how are people fixing their water problems? In this episode of Crash Course Kids, Sabrina talks about a few different examples how some freshwater sources were good, then bad, then made good again. Also, Sabrina talks about parasites, fish, and dams!

///Standards Used in This Video///
5-ESS2-2. Describe and graph the amounts and percentages of water and fresh water in various reservoirs to provide evidence about the distribution of water on Earth. [Assessment Boundary: Assessment is limited to oceans, lakes, rivers, glaciers, ground water, and polar ice caps, and does not include the atmosphere.]

I'm here to tell you not to panic, just keep calm. If you watched the last episode, you might be worried because I told you that of all the freshwater on Earth, less than one percent of it is actually accessible to us on the surface. And we are using it like we've got an unlimited supply. Which, you know, we don't. But even though humans are partly to blame for the freshwater problems on our planet, some of us are working on solutions to fix the damaged freshwater systems around the world.

But how exactly have humans affected the amount of freshwater in the hydrosphere? And what are we doing to make things better?

(Big Question)

Well, I'm glad you asked. Last time, we took a look at the falling levels of freshwater in the Colorado river and the impact that had on local wildlife. So you know that freshwater levels can definitely change, but you might not know exactly what causes them to change.

Probably the biggest thing that humans do that negatively affects the hydrosphere is overharvesting. Overharvesting is when people use too much water, like on farms or factories, or for personal use in their homes or offices. Basically, overharvesting is overuse.

Pollution is another problem. When sewage or other waste from humans gets into the water, it can have a major impact on the animals that depend on it to survive. In some really bad cases, these animals can get sick or even die from living in contaminated water.

Dams are the things that humans build on rivers that can also reduce the level of freshwater. They're used to collect water from rivers so that it can be redirected from different places, but dams also keep rivers from running their full natural course. Cutting off the natural flow of a river can affect the quality of the water and also get in the way of the fish that migrate up and down rivers.

Okay, now at this point, you're probably thinking "Come on, Sabrina, get to the happier stuff!" Well, there are ways to help conserve Earth's freshwater, lots of them! But let's not just talk about how people are helping to protect our water supply, let's actually see some results.

(Investigation)

We'll first visit a freshwater system that's bouncing back from some though times thanks to some helpful humans.

This is Elwha River, an Olympic National Park in Washington State. Its looking good, right? Yeah, well it didn't always look that way though. A giant dam built nearly 100 years ago brought a lot of problems to the Elwha. All 5 species of native Pacific salmon live in this river, but the dam kept them from making their usual migration along the river every year. With less river space to call home, salmon numbers in the Elwha began to drop. Other fish were affected by the dam too. Because the water around the dam stayed in one place for longer than normal, the water got warmer than the fish were used to. This was a problem for 2 reasons: 1 - Most fish prefer to lay their eggs in cold water, and 2 - Warm water breeds parasites, which led to more disease in the fish. And, which led to fewer fish as the years went on.

So in 2011, some local people decided it was time for the dam to come down, and by early 2012 it was gone. And the work to fix the Elwha was underway. Since the dam has come down, almost 160 kilometers of habitat have been restored for the salmon species in the river. And today the Elwha is looking awfully lovely. Plus its not the only river getting a new look.

Since 1999, about 430 dams have been torn down across the United States, allowing rivers to return to their natural flows. Removing dams isn't the only thing humans are doing to pitch in. Groups have set aside some freshwater systems as protected areas to keep them from being polluted or over harvested. And you can help by doing really really really simple things, like taking shorter showers or turning off the faucet when you brush your teeth.

The Elwha still has a long way to go before its fully restored, but if super cool humans keep pitching in, it might get there one day.

(Conclusion)

So while some humans in the biosphere do pollute and over harvest our freshwater, some are doing everything they can to protect the hydrosphere. Water you waiting for? Get out there and save some water.